Figure 4.

Effect of isoquercitrin on viral attachment, entry, and virucidal stages. (A–C) For checking the effect of IQC on the attachment stage, RAW 264.7 cells were cotreated with PR8-GFP IAV at 10 MOI and IQC at 25 µM for 30 min at 4 °C. After washing, the cells were incubated for 24 h at 37 °C. To examine the effect of IQC on the entry stage, the cells were infected with 10 MOI PR8-GFP IAV at 4 °C for 30 min, followed by the treatment of 25 µM IQC for 30 min at 37 °C. After washing, the cells were incubated for 24 h at 37 °C. For investigation of the effect of IQC on the virucidal stage, 10 MOI PR8-GFP IAV and 25 µM IQC were mixed and incubated for 30 min at 4 °C. The cells were added with the mixtures and incubated for 30 min at 37 °C. After washing, the cells were incubated for 24 h at 37 °C. (A) The cell images were captured using fluorescence microscopy with 200× magnification. (B,C) The cells were fixed with paraformaldehyde and analyzed using FACS. The levels of GFP expressed in the cells were calculated by comparison with PR8-GFP IAV. The data represent the mean ± SD value based on three independent experiments. Statistical significance was assessed via an unpaired Student t-test. *** p < 0.0001.